In the anchored scenario, the conventional version of MAIC relies on randomization in the index trial. An advantage of 2SMAIC is that, due to incorporating a treatment assignment model, it is also applicable where the index study is observational. In this case, within-study randomization is not leveraged and concerns about internal validity must be addressed by including potential confounders of the treatment-outcome association in the treatment assignment model. The estimation procedure for the trial assignment weights does not necessarily need to be that of Signorovitch et al. [1]} and alternative methods could be used [2]}, [3]}. Further modules could be incorporated to account for missingness [4]} and non-compliance [5]}, e.g. dropout or treatment switching, in the index trial.
